Answer:
The time he can wait to pull the cord is 41.3 s
Explanation:
The equation for the height of the skydiver at a time "t" is as follows:
y = y0 + v0 · t + 1/2 · g · t²
Where:
y = height at time "t".
y0 = initial height.
v0 = initial velocity.
t = time.
g = acceleration due to gravity (-9.8 m/s² considering the upward direction as positive).
First, let´s calculate how much time will it take for the skydiver to hit the ground if he doesn´t activate the parachute.
When he reaches the ground, the height will be 0 (placing the origin of the frame of reference on the ground). Then:
y = y0 + v0 · t + 1/2 · g · t²
0 m = 15000 m + 0 m/s · t - 1/2 · 9.8 m/s² · t²
0 m = 15000 m - 4.9 m/s² · t²
-15000 m / -4.9 m/s² = t²
t = 55.3 s
Then, if it takes 4.0 s for the parachute to be fully deployed and the parachute has to be fully deployed 10.0 s before reaching the ground, the skydiver has to pull the cord 14.0 s before reaching the ground. Then, the time he can wait before pulling the cord is (55.3 s - 14.0 s) 41.3 s.
Answer:
255 metres
Explanation:
The answer to thi question is actually quite simple. Since the car goes for 3.4 seconds, and it goes 75 metres every second, the answer is just 3.4 multiplied by 75 Metres.
Typical examples of inelastic collision are between cars, airlines, trains, etc.
For instance, when two trains collide, the kinetic energy of each train is transformed into heat, which explains why, most of the times, there is a fire after a collision. However, the momentum of the two trains that are involved in the collision remains unaffected. So, the trains collide with all their speed, maintaining their momentum, yet their kinetic energy is transformed into heat energy.
Another way to explain a train or a car collision is this: when the two trains or cars collide, they stick together while slowing down. They slow down because their kinetic energy is gradually lost. Still, they collide because they conserve their momentum.
A) Radio waves are a form of electromagnetic radiation.
TRUE
It is the type of electromagnetic wave with least energy range and longest wavelength range among all
B) Electromagnetic radiation does not require a medium to travel.
TRUE
This radiation can travel through vacuum also and its speed is maximum in vacuum
C) In a vacuum, electromagnetic radiation travels at the speed of light.
TRUE
speed of all electromagnetic radiation is same as speed of light in vacuum
D) Electromagnetic radiation travels in the form of longitudinal waves.
FALSE
All electromagnetic radiation is always in form of transverse waves
So correct options are
<u>A, B, C</u>
Answer:
Explanation:
plate separation = 2.3 x 10⁻³ m
capacity C₁ = ε A / d
= ε A / 2.3 x 10⁻³
C₂ = ε A / 1.15 x 10⁻³
= 
a ) when charge remains constant
energy = 
q is charge and C is capacity
energy stored initially E₁= 
energy stored finally E₂ = 
=
= 
= 
= 4.19 J
b )
In this case potential diff remains constant
energy of capacitor = 1/2 C V²
energy is proportional to capacity as V is constant .
= 16.76 .
